Method and arrangement for producing webs of material that have discrete pieces of material mounted thereon

ABSTRACT

A method of producing material in the form of a material web ( 4 ) that has discrete pieces of material ( 6 ) mounted thereon without the using of an adhesive agent and while using only one single anvil roll, and an arrangement ( 10 ) for carrying out the method and comprising an anvil roll ( 2 ) which rotates about its longitudinal axis and which is intended to be partially embraced by or be tangential to said web ( 4 ), said roll ( 2 ) carrying sequentially as seen in its direction of rotation at least one cutting means ( 1 ) for cutting discrete pieces from a material ( 6 ),and a bonding or fastening ( 5 ), such as ultrasound welding means, wherein the anvil roll ( 2 ) forms a counterpressure means for a coaction with the cutting means ( 1 ) and the bonding means ( 5 ), wherein said roll includes said holding means ( 7 ) for holding the cut discrete pieces of material ( 6 ) against the roll ( 2 ) prior to bonding or fastening said discrete pieces to said web by means of said bonding means ( 5 ).

FIELD OF INVENTION

The present invention relates to a method of producing webs of materialthat have discrete pieces of material mounted thereon. The inventionalso relates to an arrangement for carrying out the method.

BACKGROUND OF THE INVENTION

The manufacture of certain sheets of material that are intended for theproduction of absorbent articles for instance, such as diapers, sanitarynapkins, incontinence protectors, panty liners and like articles,sometimes comprises mounting and bonding discrete pieces of material onand to travelling webs of material. These discrete pieces are normallyglued to the web, although they may alternatively be welded, there beingrequired several so-called anvil rolls against which the travelling webis pressed and passes tangentially thereto or is partially embraced byone of the anvil rolls carrying said pieces of material, wherewith saidpieces are brought into contact with the travelling web by means of saidanvil roll.

The transfer of cut pieces of material from the anvil roll to thetravelling web is often facilitated with the aid of glue or some otheradhesive agent In this regard, the cut pieces of material are adhered tothe anvil roll and then transferred to the travelling web as said weblies against the anvil roll, by virtue of rotation of said roll. The useof glue in this process increases the “stop time” and therewith lowersproductivity and also increases material consumption, which has anegative affect on the price of the product, among other things.

JP-A-8052696 describes a cutting unit for cutting sanitary articles froma roll of material. The cutting unit includes an anvil roll and acutting roller which are arranged opposite one another. The sanitaryarticles cut from the reel of material are sucked firmly to the surfaceof the cutting roller and transferred to a feed roll.

One problem associated with the use of the same anvil roll for cutting(clipping), transferring and bonding the pieces of material to the webis that an adhesive agent, such as glue, is required to this end. If thepieces of material are to be welded to the web for instance, it isnecessary in the case of present technology to hold the loose pieces ofmaterial firmly during different transfer occasions between severalanvil rolls. This requires the provision of more equipment and impairsthe accuracy in which the pieces of material are applied to the web,resulting in poorer product quality.

It is thus desirable to be able to utilise one and the same anvil rollfor all phases without needing to use glue or any other adhesive agent.

SUMMARY OF THE INVENTION

The object of the invention is to solve the aforesaid problems. Thisobject is achieved in accordance with the invention with a method andwith an arrangement for producing webs of material that have pieces ofmaterial mounted thereon, said method and arrangement comprising the useof one single anvil roll which cuts, accelerates, transfers and joinsthe discrete pieces of material to the travelling web in the absence ofglue or any other adhesive agent The pieces are mounted on the web byvirtue of the anvil roll comprising means for holding said piecesagainst the anvil roll subsequent to cutting out said pieces, fortransferring said pieces to the travelling web and for fastening saidpieces thereto.

According to one preferred embodiment of the invention, the methodcomprises the steps of:

cutting discrete pieces from at least one material with the aid ofcutting means, preferably in the form of a rotating cutter roll whileusing the anvil roll as a counterpressure means;

firmly holding and applying said discrete pieces onto at least one webof material that moves against the anvil roll, by using the anvil rollas a transfer element;

fastening said discrete pieces to said at least one travelling web withthe aid of fastener means, wherein said pieces are mutually separated bycutting, accelerated whilst firmly held and then fastened or bonded tosaid at least one web of material, without the use of adhesive agent,through the medium of one and the same anvil roll and by means of saidfastening means whilst using the anvil roll as a counterpressure, meanseven when fastening said discrete pieces to said web, and wherewith thediscrete pieces are held firmly by means of holding means provided onthe anvil roll, said pieces and said web running together against theanvil roll before and after bonding of said pieces to said web.

According to another preferred embodiment of the invention, thearrangement for carrying out the method includes an anvil roll which isrotatable about its longitudinal axis and which is partly embraced by ortangential to said at least one web of material and which carriessequentially in its direction of rotation means for cutting discretepieces from at least one material, and means for fastening or bondingsaid discrete pieces to said web, wherein the anvil roll includesbetween said cutting means and said fastening means further means whichfunction to hold the discrete pieces of material against the roll priorto fastening said pieces to said web with the aid of said fasteningmeans.

The pieces of material are preferably held to the anvil roll by suction,wherewith the means for holding said pieces may, for instance, comprisevacuum generating means, means that utilise static electricity or amechanically working device.

The pieces are preferably fastened to the web by welding, such asultrasound welding, or by some other type of heat-applying method and/ordevice, such as a hot roll, laser, thermobonding device, etc.

A significant advantage afforded by the inventive method and theinventive arrangement resides in the simplification that is achievedwith the use of solely one single anvil roll for all of the stepsinvolving cutting, accelerating, and transferring pieces of material tothe travelling web of material and fastening said pieces to said web. Afarther advantage is that it is not necessary to use glue or some otheradhesive agent to fasten said pieces to the web. Furthermore, since thepieces of material and the web runs together against the anvil rollbefore and after bonding it is easy to control and synchronise thefeeding thereof to the bonding device and allow ample time for coolingof the bonds.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in more detail with reference to theaccompanying drawing, in which

FIG. 1 illustrates schematically one embodiment of an inventivearrangement.

DETAILED DESCRIPTION OF THE INVENTION

The invention shall not be considered to be limited to the embodimentdescribed below, as a number of further modifications are conceivablewithin the scope of the accompanying claims.

The arrangement 10 shown in FIG. 1 comprises a cutting roller 1, ananvil roll 2, and associated guide rollers 3. A web of material 4 ontowhich pieces of material shall be mounted moves in abutment with theanvil roll 2 in the arrowed direction, with an infeed angle α and arelief angle β. The size of the surface a with which the web 4 is inabutment with the anvil roll 2 and the angles α, β are adjusted bycommensurate adjustment of the two guide rollers 3 in a vertical or ahorizontal direction, as illustrated with the double-headed arrows.

As the web 4 lies against the anvil roll 2, welding energy is applied,appropriately with a welding device 5, so as to fasten or bond thepieces 6 to the travelling web 4. The welding device 5 may comprise anultrasound welding device that includes a horn. When welding, it issuitable to use positional control of the horn so as to maintain thecorrect distance between welding horn and anvil pattern. Alternatively,any other appropriate type of heat applying device can be used insteadof a welding device, such as a heating roll, laser or like device.

The web 4 is relieved from the anvil roll 2 at a relief angle β, suchthat the web 4 will have time to cool down (if necessary) subsequent tobonding the pieces of material thereto and prior to pulling the web 4from the anvil roll 2. After said bonding process, the coolingtemperature and cooling time must be adapted with respect to thequantities of material used and also with respect to the materials fromwhich the web 4 and said pieces 6 are comprised.

The discrete pieces of material may comprise wadding, adhesive tape,etc.

The web may consist of polypropylene, polyethylene, etc.

The relief angle β can be varied to provide different cooling timessubsequent to bonding or fastening the discrete pieces to the web.

When using an anvil roll that has two holding devices, as in the case ofFIG. 1, the relief angle β may suitably vary between 0 and 270°. Otherangles apply with other numbers of holding devices. Although not shown,it is also possible to cool subsequent to applying said discrete pieces,suitably with the aid of some form of cooling device.

The material 9 from which said discrete pieces 6 are formed is fed inbetween the cutter roll 1 and the anvil roll 2, wherewith the cutterroll 1 cuts the material into appropriate discrete pieces 6 against theanvil roll 2, said pieces being held firmly to the anvil roll 2 byholding means 7, such as vacuum means or the like. The cut pieces 6 aretransported on the barrel surface 8 of said anvil roll 2 as said rollrotates about its longitudinal axis at a constant or varying speed,which is clockwise in the case of the embodiment illustrated in FIG. 1.

The pieces are suitably cut at a relief angle β of 0°, normally verticalabove the fastening point.

Web speeds, fastening times, such as weld times, and rotational speedswill depend on material qualities, weights per unit area, fasteningmethods, e.g. different welding patterns, weld gap and the number ofcutters (knives) on the cutting roll.

It is essential that the bond that joins the discrete pieces 6 to thetravelling web 4 is strong enough to resist the force occurring when theweb 4 is relieved from the anvil roll 2.

It has also been found that the contact angle α between the anvil roll 2and the travelling web 4 can be varied. This can influence the infeed ofthe travelling web into the gap or nip between the anvil roll and thebonding device, and can also influence the accuracy with which thediscrete pieces 6 are applied. For instance, when using an anvil rollthat has two holding device, as in FIG. 1, and said pieces are welded tothe web, the contact angle α will preferably be between 0 and 160°.Other angles apply in the case of different numbers of holding devices.

When using an anvil roll that has two holding devices, as in FIG. 1, theangle γ between the cutting roll and the bonding device will preferablybe between 90 and 180°. However, this angle will depend on the distancebetween cutting point and bonding point, e.g. welding point, so that thebond is not affected by vibrations from the cutting roll. Other anglesapply with different members of holding devices.

What is claimed is:
 1. A method of producing material in the form of amaterial web that has mounted thereon discrete pieces of materialintended for use in the manufacture of absorbent articles, said methodcomprising the steps of: cutting discrete pieces from at least onematerial with the aid of a cutter while using an anvil roll as acounterpressure roll; firmly holding the discrete pieces cut by thecutter on the anvil roll so as to transfer said discrete pieces onto atleast one web of material that is guided into contact with the anvilroll; bonding the discrete pieces of material to said at least onetravelling web while being in contact with the anvil roll with the aidof bonding means, and guiding the at least one web of material intocontact with the anvil roll along a portion of the circumference of theanvil roll so that said discrete places and said web are runningtogether against the anvil roll before and after bonding of said piecesto said web, the holding and the bonding being made in the absence ofany adhesion agent, wherewith the discrete pieces are held firmly bymeans of holding devices provided on the anvil roll.
 2. A methodaccording to claim 1, characterised by holding said discrete pieces withth aid of a vacuum.
 3. A method according to claim 1, characterised byholding said discrete pieces by means of static electricity.
 4. A methodaccording to claim 1, characterised by holding the discrete piecesmechanically.
 5. A method according to claim 1, characterised byheatbonding said discrete pieces.
 6. A method according to claim 5,characterised wherein by weld-bonding said discrete pieces.
 7. A methodaccording to claim 5, characterized by bonding said pieces with the aidof a heat delivering device.
 8. An arrangement for bonding or joiningdiscrete pieces of material to material in the form of at least onetravelling web, intended for use in the manufacture of absorbentarticles, said arrangement comprising an anvil roll which rotates aboutits longitudinal axis and forms a counterpressure means of a cuttingmeans for cutting discrete pieces from at least one material and of abonding means or fastening means, the cutter and the remaining parts ofthe bonding means being located at different locations around theperiphery of the anvil roll, the cutter being placed first as seen inthe direction of rotation of the anvil roll, wherein the anvil roilincludes holding means for holding said discrete pieces to said web withthe aid of said bonding means, and the arrangement includes means forholding the web In abutment with the anvil roll before and after passageof the bonding means.
 9. An arrangement according to claim 8, whereinthe holding means is a vacuum suction means.
 10. An arrangementaccording to claim 8, wherein the holding means utilizes staticelectricity.
 11. An arrangement according to claim 8, wherein theholding means is a mechanical device.
 12. An arrangement according toclaim 8, wherein the bonding device is a welding device.
 13. Anarrangement according to claim 8, wherein the bonding device is a hotroll.
 14. An arrangement according to claim 8, wherein the cutting rolland the bonding means are disposed essentially in fine with each otheron opposite sides of the anvil roll, wherein an angle γ between cuttingpoints and welding points ≈180°.
 15. An arrangement according to claim8, characterised by guide rollers which are adapted to vary the size ofan abutment surface a, wherewith said at least one material web abutsthe anvil roll, and in that the guide rolls can be adjusted verticallyand laterally.
 16. A method according to claim 1, wherein the absorbentarticles are diapers, pants-type diapers, sanitary napkins, andincontinence protectors.
 17. A method a according to claim 5,characterized by ultrasound welding said pieces.
 18. A method accordingto claim 7, wherein the heat delivering device is a heating roll.
 19. Anarrangement according to claim 8, wherein the absorbent articles arediapers, pants-type diapers, sanitary napkins, and incontinenceprotectors.
 20. An arrangement according to claim 12, wherein thewelding device is an ultrasound welding device.
 21. An arrangementaccording to claim 11, wherein the mechanical device is an edge thatprojects out radially from the anvil roll.
 22. A method according toclaim 1, wherein the cutter is in the form of a rotary cutter roll.